Apparatus for producing high tenacity artificial yarn and cord



Sept. 30, 1952 H, D MERlON ETAL 2,611,925

APPARATUS FOR PRODUCING HIGH TENACITY ARTIFICIAL YARN AND COR-D Original Filed Nov. 23, 1948 INVENTORS HOWARD D. MER/ON l ENRY a. MCDERMOT7 ATTORNEY- Patented Sept. 30, 1952 UNITE' APPARATUS FOR PRODUCING-HIGH TENAC- ITY ARTIFICIAL YARN AND CDRD.

Howard D. Merion, West Chester, and} Henry J.

McDermott,

Collingdale, Pa.,

assignors to American Viscose Corporation, Wilmington, Bel, a corporation of Delaware Original application November 23, 1948, Serial No. 61,542. Divided and this, application September 6, 1951, Serial No. 245,306

Claims.

This invention relates to the production of high tenacity artificial filamentary yarns and cord from regenerated cellulose by the viscose process, and has as its object an improved apparatus adapted to produce yarns and cords having increased flexing life. This application is a division of our application Serial No. 61,542, filed November 23, 1948.

In accordance with the present invention, it has been found that improved regenerated cellulose yarns and cords having high tenacity and long flexing life can be obtained by spinning a viscose having a temperature of at least 30 G. into a regenerating coagulating bath having a temperature of 40 to 75 C. or higher, stretching the partially regenerated filaments between 40 and 80%, washing out the acid while completing the regeneration of th filaments, relaxing, drying, and collecting by winding and/ or twisting.

The viscose to be spun proceeds from the ripening and filtering equipment which is usually disposed in a separate room, commonly in a basement where a low room temperature from 18 to 22 C. may be maintained. As such viscose proceeds through the lines to the spinning machine in the spinning rooms, it may absorb some heat and rise to a temperature of 25 to 28 C. by the time it reaches the spinnerets of the machine. In order to raise the temperature into the range of at least 30 0., means is provided for heating a portion of the line through which the viscose passes on its way to the spinnerets. While the heating means could be applied to a common system for feeding a number of machines in the spinning room, or to the header associated with each spinning machine, it is preferredfor reasons stated hereinafter to provide a system of heating the individual supply lines leading to the spin nerets. For example, electric heating coils, ,high frequency electrostatic heating devices, orheating baths maybe applied to the viscose lines. The individual supply line or rounder may comprise a tortuous channel made by bending a portion of its length into the form of a helical coil, and this rounder may be submerged in the spinning bath to derive its heat from such bath or it may be submerged in some other liquid bath having a sufficiently high temperature to heat the viscose to the proper temperature. When a hot aqueous liquid (at 60 to 100 C.) is used for treating the yarns before, after, or during stretching, the hot liquid can be circulated through the yarn-treating stage and the viscoseheating stage in succession in either order.

It has been found that it is necessary not only 2 to have the viscose at a proper-temperature but also to relax the filaments in an amount of the order of, 3 to 10% after stretching and before orduring drying in order to obtain a combination of a high tenacity and exception-ally long flexing life. 7

Before drying the yarn and after it has been rendered acid-free, a soft finish may be obtained by the application of sodium oleate, polyvinyl alcohol, ethylene oxide, modified sorbitan dipalmitate, or compositions containing such ingredients insuitable proportions. If desired, desulfurization, bleaching, may be applied with appropriate intermediate washes. Such treatments should precede the application of a softener when such softener is desired to be applied to the product. Depending upon the use to which the yarn obtained is intended to be put, it may be collected with or without twist. When it is desired to produce tire cord from such yarn, it is generally preferred to collect the individual yarns with a predetermined amount of twist so that a subsequent doubling operation may serve to combine the desired number of individual plies in th final cord with the proper twist in the plies and the cord respectively.

In the-following examples, the relative fatigue rating or flexing life is determined on the flexing machine of the U. S. Rubber Company, in which a number of the cords are assembled in parallel relationship into a ribbon or band 30 inches long and the ribbon. thus obtained is secured at the opposite end within two jaws, the upper of which i reciprocated /2 inch from the initial setting with the band's tau-t at a. frequency of 500 per minute. A tension device on the lower jaw takes up any slack developed because of permanent elongation during the test. This flexing is carried out at a temperature of about 120 F.

The viscose employed may have from 6 to 8% cellulose, (which may be wood, cotton, linters, or any mixture thereof, preferably from 50 to 100% cotton) -6 to 3% caustic, and 30 to .40% carbon disulfide based on the cellulose in the viscose. The salt test maybe from 3 to 6 and the ball fall viscosity before heating'may be from 40 to 200 seconds.

The spinning bath maycontain from 7 to 12%- sulfuric acid, 15 to 25% sodium sulfate, and from 1 to 10% of the sulfate of zinc, magnesium, or iron, or a mixture of the latter sulfates.

The viscose preferably should have a temperature of 45 C. to C. and the bath a temperature of 50 to C. In the prefer-red instance the and such procedures difierence in temperature between the viscose and spinning bath is not over 10 C. and the optimum difference is about C. to C.

The drawing illustrates a preferred embodiment of equipment in accordance with the present invention. As shown, the single figure represent a schematic view in perspective with parts in section.

As shown, the viscose is fed to the machine through a header 3 to which there are connected a number of branch outlets t connected to the individual spinning pumps 5 of positive displacement type, such as ordinary gear pumps. The discharge lines 6 from the individual pumps 5 lead to a candle filter I through a swivel joint la which allows swinging of the candle filter l and rounder 8 in a counterclockwise direction as viewed in the figure, to remove the spinneret 9 out of the coagulating bath contained within the receptacle 10, which may be a trough extending the length of the machine or individual receptacles, one for each spinneret. A feed pipe H serves to supply the coagulating bath to the receptacle l0 and an overflow pipe 12 displaced from H longitudinally of the machine serves to control the level of the bath in the trough i0 and assures circulation of the bath past the spinneret or spinnerets 9.

A receptacle I3 is provided alongside receptacle l0 and may be insulated therefrom by a layer M of material of low heat-conductivity. Like I0, the receptacle 13 may be individual for each rounder or it may be a trough running the length of the machine. An overflow pipe 15 is provided for controlling the level of heated liquid in the predetermined number of wraps of the yarn are wound to provide further regeneration prior to stretching. The yarn leaves the upper rotor i5 and passes through container 18 for a hot aqueous liquid continuously supplied thereto from a pipe l9. hot water, hot dilute acids or salts, and may for example contain from 1 to 5% sulfuric acid, 1 to 3% sodium sulfate, and to l%% of zinc sulfate. As shown, the overflow pipe 20 in the container l8 discharges into the container 63 for heating the viscose in the tortuous channel 8a. A thread-advancing reel or equivalent threadadvancing device 21 rotates at a peripheral speed from 4 0 to 80% higher than the peripheral speed of rotors l5 and i i, to provide the stretch needed at this stage. On the reel 2!, a washing liquid, such as cold or hot water, cold or hot dilute acid or salt solutions, such as a solution containing from 0.1 to 0.5% sulfuric acid, is supplied from a spray or shower head 22, and additional wash water may be sprayed on the reel by spraying head 22a, and the yarn departing from reel 2! passes under a pulley or rotor 23 immersed in a bath of a soft finish in a container 24 and then it proceeds around a thread-advancing device for drying comprising a pair of rotors 25 and 26 which are driven at a peripheral speed at the yarn-receiving portion somewhat less than the peripheral speed of discharge from reel 2 i. The surfaces of the rotors 25 and 26 may have in- The aqueous medium may be termediate tapered portions 21 and 28 respectively to allow further shrinkage of the thread during the drying as it reaches this portion of the device. This taper may amount to 3 to 10%. If all of the shrinkage is carried out on the tapered portion of the rotors 25 and 20, their peripheral speed at the yarn-receiving end may be the same as the peripheral speed of the reel 2| and all shrinkage may be performed on the drums. On the other hand, the differential in the speed between the drums 25, 2B and reel 2i may be sulficient to take care of all the shrinkage desired, in which case the drums 25 and 26 may be cylindrical throughout their length. General- 1y, it is preferred to have a portion of the shrinkage occur before the drying drums 25 and 28 are reached, and a portion of the shrinkage occurs on an intermediate portion of the dryer drum where the moisture content has been reduced to about 150% based on the weight of the yarn.

After the yarn departs from the drums or otherwise heated rollers 25 and 26, it is collected by winding or by winding and twisting at 29.

Example I A viscose containing 7.8% cellulose, 6.6% caustic, 36% carbon disulfide (CS2 based on the alpha cellulose content of the pulp) and having a salt point of 5 as determined with sodium chloride was spun into a bath containing 10% sulfuric acid, 4.5% zinc sulfate and 21% sodium sulfate at C. to produce a 1650 denier, 980 filament yarn. The rounder comprised a l-foot long stainless steel helical coil immersed in hot water at C. The viscose was heated to 45 C. and the immersion travel of the filaments in the bath was 12 inches at a spinning speed of 107 meters per minute. A 16-yard storage was used on the rotors l6 and I! of the drawing and immediately thereafter the yarn was stretched Hot water at about C. was used in trough 18. After washing to a neutral condition, the yarn passed through a soft finish and was allowed to relax a total of 8%, about 5% on the way to the drying stage and about 3% on a ta ered portion of the drying drums. The yarn produced had a dry tenacity of 3.63 grams per denier, a dry elongation of 11.9%, a wet tenacity of 2.28 grams per denier, a wet elongation of 22.0% and a fatigue rating of 135.

The same viscose spun into the same bath and under the same conditions, except that the viscose was not heated but had a temperature of 270 C. as it issued from the spinneret, yielded a yarn having a dry tenacity of 3.65 grams per denier, a dry elongation of 10.8%, a wet tenacity of 2.21 grams per denier, a, wet elongation of 20.7, and a fatigue rating of 114. When this same procedure is carried out without relaxation and. without heating of the viscose, a fatigue rating of 47 to 60 is generally obtained.

Example II Viscose was spun under the same conditions as in Example I and was heated to a temperature of 45 C., except that the storage on the rotors l5 and I! was reduced to 2 yards. The resulting yarn had a, dry tenacity of 3.43 grams per denier, a dry elongation of 12.8% a wet tenacity of 2.21, a wet elongation of 20.5, and a fatigue rating of 180. This shows the great improvement obtainable by stretching filaments in a less completely regenerated condition.

The following table lists additional examples using the same conditions as Example 11 except the shrinkage or relaxation on the way to the drying stage was reduced to 4% and the temperature was varied as indicated.

ments comprising a container for a coagulating bath, a second container adjacent the first, a conduit system pivotally mounted on an axis Viscose Dry Dr Wet y Ext, Wet Ext., Fatigue Example i a?" Denier gf f q Percent i fif Percent Rating A comparison of the results shown in the preceding illustrative examples shows the exceptionally good flexing life and how this has been increased by the present invention without any sacrifice in the tenacity of the yarn. In general, it has been found that the heating of the viscose just before spinning gets rid of so-called native cellulose, so that a more uniform filament is obtained. Apparently this reduction or complete elimination of native cellulose renders the substance of the filament more amenable to the subsequent processes of stretching and relaxation so that the final product has remarkably improved flexing life without any decrease in tenacity. The reason for such improvement is not clearly understood, but it is clear that stretching should be performed on the filaments while still undergoing regeneration, and preferably before the regeneration has been A to completed.

The product of the present invention can be used for the production of filament yarns or staple fiber yarns where high tenacity regenerated cellulose filaments or fibers are desired. It is particularly advantageous in the production of cords used for reinforcing rubber goods, such as tires, belts, and the like.

It is to be understood that changes and variations may be made without departing from the spirit and scope of the present invention, as defined in the appended claims.

We claim:

1. An apparatus for spinning artificial filaoutside the containers comprising a pipe having a portion thereof formed into a tortuous configuration, a spinneret on a terminal portion of the pipe away from the axis, said tortuous portion and spinneret being ofiset laterally in the same direction from other parts of the pipe whereby swinging of the pipe in one direction introduces the spinneret into the first container and the tortuous portion in the second container, and swinging in the other direction removes the spinneret and tortuous portion from the containers.

2. Apparatus in accordance with claim 1 in which the tortuous configuration comprises a generally helical coil.

3. Apparatus in accordance with claim 1 comprising means for applying a hot liquid to the filaments outside the two containers, and means for directing said liquid to the second container.

4. Apparatus in accordance with claim 3 comprising means for stretching the fiaments during the application of the liquid.

5. Apparatus in accordance with claim 4 comprising means for washing the stretched filaments, means for drying the washed filaments, means for relaxing the filaments prior to completion of drying, and means for collecting the dried filaments.

HOWARD D. MERION. HENRY J. MCDERMOTT.

No references cited. 

1. AN APPARATUS FOR SPINNING ARTIFICIAL FILAMENTS COMPRISING A CONTAINER FOR A COAGULATING BATH, A SECOND CONTAINER ADJACENT THE FIRST, A CONDUIT SYSTEM PIVOTALY MOUNTED ON AN AXIS OUTSIDE THE CONTAINERS COMPRISING A PIPE HAVING A PORTION THEREOF FORMED INTO A TORTUOUS CONFIGURATION, A SPINNERET ON A TERMINAL PORTION OF THE PIPE AWAY FROM THE AXIS, SAID TORTUOUS PORTION AND SPINNERET BEING OFFSET LATERALLY IN THE SAME DIRECTION FROM OTHER PARTS OF THE PIPE WHEREBY SWINGING OF THE PIPE IN ONE DIRECTION INTRODUCES THE SPINNERET INTO THE FIRST CONTAINER AND THE TORTUOUS PORTION IN THE SECOND CONTAINER, AND SWINGING IN THE OTHER DIRECTION REMOVES THE TAINERS. 